Electric-lamp indicator



Jan. 12 1926. 1,569,460

- R. B. CRESSMAN ELECTRIC LAMP INDICATOR Filed July 2 1923 IN VEN TOR BY 2 ATTORNEY Patented Jan. 12, 1926.

RUSSELL n. CLRESS'MAN, or rnrnnnnnrnin, PENNSYLVANIA.

ELECTRIC-LAMP INDICATOR.

Application filed July 2,1923. Serial No. 549,099.

To all whom it may concern: v

Be it known that I, RUSSELL B. CRESSMAN,

a citizen of the United States, residing at Philadelphia, in the county'of Phi1a- 5 delphia and State of Pennsylvania, have in-- vented certain new and useful Improvements in Electric-Lamp Indicators, of which the following is a specification.

This invention relates to electric lighting fixtures or appliances and has particular reference to the use of incandescent electric lamps.

It beingwell understood by those versed in the art that an electric lamp (meaning by this term an electric lamp bulb as'a unit) may glow freely and give satisfactory white appearanceand light for. a certain number of hours but thereafter the ,light becomes gradually yellowish, due to the increase in the red and spondingly dimmer and less efficient, even though the consumption of electricity may not be reduced in proportion to the efficiency of the lamp. In other words,.I have observed that electric lamps should be discarded and replaced much more frequently than they are, largely .due either to carelessness or to the inability for theowner or user of the lamps to determine with a so reasonable degree of accuracy the time when the lamp should be discarded. This latter condition obtains especially ,in connection with the modern'practice of secluding the lamps by means of globes or reflectors pertaining to the indirect or semi indirect lighting system, now commonly practiced, especially in connection with the high powered type of lamps. v v

Among the objects ofvmy invention, therefore, is to provide an indicator having the adaptability of enabling any person to observe with facility and substantial accuracy thecritical period in the life of the lamp, that time or period when the lamp is no longerefiicient or giving a full equivalent in the quantity'or color of the light for the electricity consumed thereby.

Another object of the invention is to provide what maybe termed a combined globe and indicator so constructed as to serve the usual purposes of a globe or light diffuser and an indicator of the condition of the lamp.

In carrying, out the foregoing and other allied objects of theinvention' reference is ellow light rays, and correor decidedl yellow or muddy hue.

made to the accompanyin drawing which shows one practical embo iment of the in-' ventlon.

10 indicates an electric lamp in a socket 11 constituting a part of a ceiling fixture 12. Surroundm said lamp and secured to the fixture is ag obe 13 of any suitable size, deslgn, or construction, ordinarily, however, made'of glass or the like, and of a translucent nature for the purposes already alluded to, including the diffusion of the intense light from thelamp and serving as an indicator of the condition of the lamp.

; In carrying out this invention and discovery in a practical form I construct the globe of material having a color or tint of such a character as to compel the light in passing outward therethrough to be erfectly white and so resemble natural daylight. For this purpose Ipreferably employ a blue tint for the globe, the depth of the color or tint being predetermined, however, for the special purpose now about to be more precisely set forth. After a long series of experiments I have discovered that the depth or quality of tint of a lamp globe may be so determined that the light emitted therefrom will be substantially pure white throughout the entire period of eflicient usefulness of the lamp, and then at the end of such period, or what has been referred to herein as the critical time, the light emitted from the globe will be of a pronounced That is to say, t e light from my improved indicator devices will appear either efliciently white or inefiiciently yellow, so that any observer may note readily the condition of any lampas to its condition of efficiency by simply observing the appearance of the globe. 13.

I am aware that it is not new practice to make lamp bulbs or globes of colored glass or to employ a tint of blue or any other b the globe itself. It being common knowle ge in the glass Working art how to make a blue layer in the glass or to tint the glass with blue-or other suitable coloring in various degrees of density, I wish to disclaim any general claimfor a monopoly on, the

I .idea of tinting glass or to employ a tinted lass in connection with an electric lamp: n the contrary,I wish to insist that this invention is more in the nature of a discover wherein I have discovered or ascertaine that the intensity of the color in' the glass may be so correlated to the intensity of the electric lamp light as to produce the effect herein set forth. In the practice of this discovery the amount of blue or other suitable color in the lass 13, no matter by what chemical or mec anical process it is so supplied, is sufiicient to kill. the red and yellow rays of the lamp during and only acter of light at the end of such period.

period, the timewhen its usefulness is no longer eflicient. For thesereasons it is main-' tained that the invention or discovery is in the nature of an indicator of the period of usefulness of the lamp, rather than in the general idea of maln'ng a tinted lamp globe.

I claim:

1. The combination with an electric lamp having a substantially predetermined period of illuminating efiiciency, of a combined globe and indicator therefor having a color component of a quality and depth sufficient to serve to emit substantially white light from the lamp during such period aforesaid and then to show a distinctly difi'erent char- 2. The erein described electric lam indicator consisting of a glass globe of tinted composition of predetermined depth through which light is designed to pass and be made to appear substantially white for a predetermined time, according to the period of eflicient usefulness of the lamp producin the light, and then to indicate directly and automatically by a different color of light that the eriod aforesaid has passed.

In testimony whereof I aflix my signature.

RUSSELL B. CRESSMAN. 

